GetRequestStream() is throwing time out exception when posting data to HTTPS url

Question

I\'m calling an API hosted on Apache server to post data. I\'m using HttpWebRequest to perform POST in C#.

API has both normal HTTP and secure layer (HTTPS) PORT on the

Answer 1

I ran into this, too. I wanted to simulate hundreds of users with a Console app. When simulating only one user, everything was fine. But with more users came the Timeout exception all the time.

Timeout occurs because by default the ConnectionLimit=2 to a ServicePoint (aka website). Very good article to read: https://venkateshnarayanan.wordpress.com/2013/04/17/httpwebrequest-reuse-of-tcp-connections/

What you can do is:

1) make more ConnectionGroups within a servicePoint, because ConnectionLimit is per ConnectionGroups.

2) or you just simply increase the connection limit.

See my solution:

private HttpWebRequest CreateHttpWebRequest(string userSessionID, string method, string fullUrl, U uploadData)
{
    HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(fullUrl);
    req.Method = method; // GET PUT POST DELETE
    req.ConnectionGroupName = userSessionID;  // We make separate connection-groups for each user session. Within a group connections can be reused.
    req.ServicePoint.ConnectionLimit = 10;    // The default value of 2 within a ConnectionGroup caused me always a "Timeout exception" because a user's 1-3 concurrent WebRequests within a second.
    req.ServicePoint.MaxIdleTime = 5 * 1000;  // (5 sec) default was 100000 (100 sec).  Max idle time for a connection within a ConnectionGroup for reuse before closing
    Log("Statistics: The sum of connections of all connectiongroups within the ServicePoint: " + req.ServicePoint.CurrentConnections; // just for statistics

    if (uploadData != null)
    {
        req.ContentType = "application/json";
        SerializeToJson(uploadData, req.GetRequestStream());
    }
    return req;
}

/// 
Serializes and writes obj to the requestStream and closes the stream. Uses JSON serialization from System.Runtime.Serialization.
        
public void SerializeToJson(object obj, Stream requestStream)
{
    DataContractJsonSerializer json = new DataContractJsonSerializer(obj.GetType());
    json.WriteObject(requestStream, obj);            
    requestStream.Close();
}